<span class="highlight">CARAVAN</span> LIGHTS ON CARS WITH REVERSING SENSORS

Why. What do resistors do to cause flashing?

You fit resistors to stop the flashing
Some vehicles pulse the line to see if there is a trailer connected. With a filament globe there isn't enough power in the pulse to light the filament but LED's dont present enough of a load thus the light. Ford released an adaptor to correct this and charged $150 for it and all it was was a plug, a socket and a couple of 17 cent resistors.

Ivan - 17 cent resistors?? Where do you get LED resistors for that price?

When I fitted LED tail lights to my Hilux, my local automotive parts supplier charged me $11.00 each for Narva resistors for the indicators!

I reckoned it was a total rort, but I still haven't found any, for anywhere near 17 cents each.

But after looking at this following eBay pricing, it looks like I got a good deal!

eBay - Narva LED resistors

Cheers, Ron,

When I bought the Ford adapter it cost me $25. The problem is definitely LED lights and the car being Euro style where the car wants to know if anything is being towed.

Not quite 27 cents, but $11 for a pack of 10 Here for example

the stop and indicator should be the next ohm size up from 6 ohms, the tail should be next size up from 20 ohms.
The tail should be 10Watt and the others 20W.

I am sure you can get away with higher value resistors, They could be lower wattage, and could well be as low as 17 cents if you know what you are doing.

Go to Jaycar and the price will be a lot less than Narva.

Why don't the vehicle lights flash if the line is being pulsed? What lights does it have LED or Globes?
Many towbar systems have Relays OR Solid State switching to detect an input from the vehicle loom and switch current from a dedicated +ve feed to the appropriate relay and then to the wire in the trailer plug.
Dmax have similar to cater for additional loads on trailer flashers. I lamp or 10 per side doesn't make any difference.

David hasn't mentioned what type of lights he has on his vehicle or van, yet.

I use these on the van and they have been there for 7 years with no problems. I also carry a Ford adaptor for other trailers I might hook up to. It was genuine and less than $20 when I bought it. 24 cents a resistor.

The resistors are in an adaptable Box with poly glands on the A-Frame, I mounted it so no stones can cause a problem, and it is easy to get too and easy to change the lead and plug if required.

Jaycar resistors to suit

https://www.jaycar.com.au/100-ohm-1-watt-carbon-film-resistors-pack-of-2/p/RR2550

RMD It's a trailer module that does it not a relay. Thats why I assumed it was a Ranger or a European car as the use modules. I'm not guessing at this. I do this for a living

I tried a few resistors on my 2014 Ranger, the highest resistance I could use was 22ohm (10W) otherwise the indicators would flash slow/fast at random intervals.

https://www.jaycar.com.au/22-ohm-10-watt-wire-wound-resistor/p/RR3356

nickb This is on the trailer not the vehicle.

Ah ok. From memory my trailer ones are around 100ohm, similar if not the same as the ones in link.

I was lucky. When Ford first had this issue the local SES brought a vehicle in with the adaptor so I opened it to see what resistors were in it. :-)

.
Good one Ivan.

David, you still haven't explained the precise circumstances that causes the van park lights to flash?

Is it happening all the time the lights are on, or just when you brake, or some other specific circumstances?

In addition, what sensors are you referring to?

Cheers, Ron.

David G
I am still trying to work out the relevance of the reversing sensors in this. It might happen only on the BMW but WHEN is it happening?
When park lights are activated on the vehicle or when they are switched off.

Have you checked the wiring in the 12 pin base AND the trailer plug too for correct pin assignment of everything for each wire colour? Made sure there are no stray wire strands between component pins too?

If the vehicle is CANBUS ( almost certain it is) and it can't take the load of the trailer globes it may turn them on and off to save the ECU circuitry. Therefore, you may need a piggy back switching device, ie power fed relay system to remove the load from the vehicle and give the supply demand to the dedicated power feed from battery. Each relay turns ON as required for trailer lamp functions.
You didn't mention if this situation had recently started or you have for the first time connected the van to the car. This creates a few unknowns for people trying to remotely diagnose and provide a possible solution.

Has it been previously been operating O.K., or has the problem started as soon as you hooked them up?

Being a BMW, we're entering minefield territory, with BMW engineering and electronics being horrendously complex, and needing specific BMW service tools to do repair work.

A friend with a BMW has found you can't use an off-the-shelf OBD-II code reader in a BMW, you need the BMW code reading scanner, it is specific to BMW.

Then again, being a new van, the problem may simply be faulty assembly work on the part of the van builder, and it could be something as simple as incorrect wiring, a faulty earth connection, or even just loose wires.

Cheers, Ron.

David.
Maybe take all but 1 globe of park globes out of van, ie. Just leave a side market globe which is low wattage and see if the pulsing stops and continuous illumination occurs. If it does it would indicate the overload of CANBUS system and an auxiliary switching device is needed to over come the situation.

David
Mazda seem to use one for towbars on CX3 . See the post a few down the page. 3 replies. Not sure for a BMW though.

David, you can buy one of these devices locally, for a sizeable sum ....

Redarc - Advanced Trailer Lighting Interface

Or - you can purchase one of these from the U.K., off eBay, and save a heap of money, because it will do the same job as the Redarc device.

eBay - Ryder Smart Logic 7-wire Bypass Relay for towing

An explanation of how the device works, and fitting instructions for the unit -

7-Way Smart Logic Module

Cheers, Ron.